Protein glycosylation is a well-established post translation modification that influences the folding (Walsh et al. (1990) Biochemistry 29(26):6250-7), solubility (Leavitt et al. (1977) J. Biol. Chem. 252(24):9018-23), immunogenicity (Shields et al., (2002) J. Biol. Chem. 277(30):26733-40; Rudd et al., (2001) Science 291(5512):2370-6; Lowe and Marth, (2003) Annu. Rev. Biochem. 72:643-91, binding (Wallick et al., (1988) J. Exp. Med. 168(3):1099-109), stability (Wyss and Wagner, (1996) Curr. Opin. Biotechnol. 7(4):409-16), and pharmacokinetics (PK) (Millward, T. A., et al. (2008) Biologicals 36(1):41-7; Gross et al., (1988) Eur. J. Biochem. 173(3):653-9; Clincke et al., (2011) BMC Proceedings 5 (Suppl 8): p 114-115) of recombinant protein therapeutics (reviewed in Hossler et al. Glycobiology (2009) vol. 19 pp. 936-949).
During the N-glycosylation biosynthetic pathway, oligosaccharides are added onto asparagine residues of protein therapeutics in a step-wise manner followed by the step-wise removal and addition of individual monosaccharides in the endoplasmic reticulum (ER), and Golgi apparatus. This progression of potential glycoforms is summarized in FIG. 1. Briefly, mannose is removed to allow the addition of N-acetylglucosamine (GlcNAc) followed by the addition of galactose. The glycosylation profile for a given therapeutic glycoprotein often includes a mixture of these different glycoforms.
The impact of protein glycosylation on the physiochemical properties of recombinant proteins is well-documented. The protein glycosylation profile is therefore a critical process parameter in the manufacturing of recombinant protein therapeutics.
For the foregoing reasons, there is an unmet need in the art for the consistent and reliable glycosylation of recombinant biologics during manufacture.